docs: def make_datalab_help_action(self):
      """Custom action for --datalab-help.
  
      The action output the package specific parameters and will be part of "%%ml train"
      help string.
      """
      datalab_help = self.datalab_help
      epilog = self.datalab_epilog
  
      class _CustomAction(argparse.Action):
  
        def __init__(self, option_strings, dest, help=None):
          super(_CustomAction, self).__init__(
              option_strings=option_strings, dest=dest, nargs=0, help=help)
  
        def __call__(self, parser, args, values, option_string=None):
          print('\n\n'.join(datalab_help))
          if epilog:
            print(epilog)
  
          # We have printed all help string datalab needs. If we don't quit, it will complain about
          # missing required arguments later.
          quit()
      return _CustomAction